Industrial process and apparatus



July 25, 1967 ROTH'ENBERG ETAL INDUSTRIAL PROCESS AND APPARATUS Filed DGO. 9, 1965 Pfg. 4

R .E EB om TH mm VR mu. E M O R E J RAYMONDANOLF ATTORNEY United States Patent O 3,332,607 INDUSTRIAL PROCESS AND APPARATUS Jerome H. Rothenberg, Dresher, Pa., and Raymond A.

Wolf, Palo Alto, Calif., assignors to Pennsalt Chemicals Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Dec. 9, 1965, Ser. No. 513,163 8 Claims. (Cl. 230--69) This invention relates to an ultra-high vacuum chamber especially a chamber for the simulation of outer space and ladapted for testing and examining units and components to be placed in outer space. More specifically this invention relates to a compact space simulation chamber with integrated pumping means including ion pumps mounted within the chamber itself in a manner such that all surfaces thereof are exposed to the inside of the chamber.

In the past, to achieve an ultra-high vacuum in, for instance, a space simulation chamber, mechanical v-acuum pumps have been used. Also ion pumps have been employed in special pumping chambers off the primary simulation chamber. Ion pumps have comprised anodecathode assemblies mounted in cubby holes in the wall of the ion pumping chamber and disposed in magnetic tields created by magnets mounted in indentations on the outside of the chamber. An example of such construction is shown in Patent 2,983,433 granted May 9, 1961. While the ion pumps as mounted in the prior art were effective to some extent in creating low vacuums toward the desired range, their efficiency has not been great as compared with the present invention.

The present invention has for an object the production of a space simulation chamber whereby the pumping action of the ion pumps is of greatly improved ellciency over the prior art structure.

The present invention involves the complete reorganization of the vacuum chamber. Whereas formerly the ion pump cathode-anode assemblies have been disposed in cubby holes in compartments off of the main vacuum chamber, under the present invention they are disposed in the vacuum chamber and are nude, that is exposed on all sides to the inside of the chamber. The ion pump components 4are spaced from the walls of the chamber so that the gas molecules can move more freely about them and hence can more readily be adsorbed.

It is, therefore, a feature of the present invention to increase the efficiency of getter ion pumping in a vacuum system by reorganizing the chamber to make the surfaces of ion pumps more accessible to the gas within the chamber.

It is a further feature of the present invention to provide a vacuum system in which the total amount of chamber wall area is reduced thereby decreasing the amount of outgassing surface.

It is a further feature of the present invention to provide a vacuum system in which pump performance is maximized by minimizing conductance losses.

It is a further object of the invention to provide a compact pumping chamber by making a cryopumping shroud within the chamber the object of a titanium sublimation device.

Other features of the present invention will be apparent from the following specification including the drawings in which:

FIGURE l is an elevational view partly simplified and schematic of the chamber embodying the invention with a part of the shell of the chamber broken away to show the arrangement of the pump structures and cryogenic shroud therewithin; the general arrangement is elsewhere shown in phantom;

3,332,67 Patented July 25, 1967 ice FIGURE 2 is a fragmentary sectional View in which the means for supporting the ion pump assembly Within the chamber is shown in section;

FIGURE 3 is a sectional view taken on the line 3-3 of FIGURE 2, and showing a mounting for the pump assembly support ring and titanium sublimator; and

FIGURE 4 is a fragmentary section view taken on the line 4-4 of FIGURE 1.

Briefly, the invention involves the organiz-ation of an ultra-high vacuum chamber wherein pumping means are disposed within the chamber proper and are spaced from the walls thereof and are freely exposed on all sides t-o increase their effectiveness.

Referring more specifically to the drawings, a chamber embodying the invention is generally designated 10 in FIGURE 1. It comprises a llanged shell 12 mounted on stationary supports 14 and having an enlarged peripheral section or belly band 16. Connections 18 of various sorts, and not comprising the invention, are provided in the shell.

End walls 20, also flanged, are secured to the end of the shell 12 by conventional means. The end walls may, if desired, respectively ride on wheeled carriages 22. Openings may be provided such yas 24 to which suitable and conventional vacuum pumping means can be connected. Access openings such as 26 permit small components to be introduced into the chamber.

As shown in FIGURE 2 the belly band 16 has mounted therein an annular ion pump support ring 28. This ring comprises an annular web 30 and a pair of flanges 32 and 34 secured to the opposite periphery thereof. As Shown in FIGURES 2 and 3, the lower end of the outer flange 32 is provided with a downwardly extending tongue 36 which is received into an opening in a box-like mount 38 having side walls 40 and secured to the bottom of the belly band. To keep the support ring laterally spaced with respect to the walls of the belly band, wings 42 are provided 'on the ring 32 on the sides thereof. These wings fit into openings on suitable brackets 44 welded to the side of the belly band.

As show'n in FIGURE 4, mounted about both sides of the ion pump support ring are the pump anodecathode assemblies 46 which include the conventional cathode plates (not shown) which may be disposed more or less radially of the ring. Between the cathode plates are the cellular anodes (not shown) which preferably comprises a plurality of contiguous open cans. In the assembly 46 the cathode plates are insulated from the cellular anodes and both are respectively lconnected to power sources. The -assemblies are available from Ultek Corporation.

Intermediate adjacent assemblies 46 there are provided the magnet units 48 which may comprise a plurality `of side-by-side magnets S0 encased in a magnetically permeable metal sheath 52. The sheath (FIG. 2) comprises the peripheral sheet 52a and the end caps 52b. The opposite end caps are attached to the ring 30 as by bolts, the opposite ends h-aving portions extending outward from the body of the capsule `and being apertured (FIGURE 4) to permit the passage of such bolts.

By virtue of the structure shown, it will be clear that much space S4 is provided on all sides of the ion pump assembly. Rather than having the cathode-anode assemblies disposed in cubby holes with their magnets on the outside of the chamber, the assemblies are now disposed in the chamber and freely spaced from the magnet units. It permits free circulation of gaseous molecules between these assemblies and eventually their trapping on the surfaces of the assemblies.

Spaced from and mounted inside the shell 12 is the cryopumping shroud 56 (shown partly schematically).

The shroud which may be tubular and be positioned centrally of the shell 12 by means not shown has super cooling lines 56a tracing through it and supplied with liquid nitrogen or other coolant to produce -a temperature in the shroud in the neighborhood of 100 K. The interior of the shroud may be painted black to represent a black absorbing environment for specimens to be placed Within the chamber to more closely simulate the conditions of outer space. End walls for the shroud may be similarly traced and similarly painted black. The exterior of the shroud is of aluminum construction, although other materials such as stainless steel, copper, etc. may be used, and its surface is a suitable object for the titanium sublimators S8, also available from Ultek Corporation, which may be stationed about a periphery of the belly band 16 as desired. The titanium sublimators may be in the form of a resistance heated filament of wound titanium wire and the titanium may be shielded so that disposition is made upon the outer surfaces of the shroud.

The various pumping components-the mechanical vacuum pump, the ion pumps, the titanium sublimators and the cryopumping shroud-may Ibe placed in operation at times which will be obvious to those skilled in the art. By means of the arrangement described, vacuums approaching 2X 10-12 torr may be achieved to closely simulate the conditions of outer space. It will be understood that by virtue of having the ion pump assemblies present in the vacuum chamber itself efiiciency of the organization is greatly enhanced. Further by providing sublimators for sublimating titanium onto the outside surfaces of the shroud noteworthy compactness of the organization is achieved which reduces the wall surface space of the chamber and decreases outgassing factors.

The present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof and, accordingly, reference should be made to the appended claims rather than the foregoing specications as indicating the scope of the invention.

We claim: Y

1. A vacuum chamber comprising a generally cylindrical housing having an annular enlargement about a portion thereof, an ion pump support ring being secured no the inside of the housing at said portion yand about the periphery thereof, a plurality of ion pump anode-cathode assemblies and magnet means, said assemblies and magnet means being mounted in alternate fashion on at least one side of the ring and spaced from the Wall of the housing so that the magnetic lines of flux of two adjacent magnet means e tend through the assembly intermediate the two magnet eans.

2. A vacuum chamber as claimed in claim 1 wherein each of said magnet means is a permanent magnet means encapsulated in a magnetically permeable metal sheath.

3. A vacuum chamber as described in claim 1 wherein the chamber is provided with a tubular shroud, the shroud having uid passages therethrough for the purpose of cryopumping, the chamber also being provided with itanium sublimating devices positioned outside the shroud and adapted to direct their output onto the outside face of the shroud.

4. A vacuum chamber comprising a generally cylindrical housing having an annularly enlarged portion in the periphery thereof, an ion pump mounting ring mounted on the wall of the housing at the portion, a plurality of magnet assemblies in the housing and comprising a magnet means, a peripheral sheet wrapped about and enclosing the periphery of the magnet means and end caps secured to the m-argins of the peripheral sheet and cornpleting the enclosure of the magnet means, the end caps extending outward from the sheet and being formed with mounting openings, and fastening means securing the magnet assemblies to the mounting ring.

5. A vacuum chamber as described in claim 4 wherein the magnetic assemblies on the mounting ring alternate with cathode-anode assemblies.

6. A vacuum chamber as described in claim 4 wherein the ring is provided with a plurality of spaced outward projections, and the wall of the housing is provided With a plurality of openings and the ring is mounted in the housing by having the projections extending into the openings.

7. A vacuum chamber comprising a generally cylindrical housing containing a cylindrical shroud having fluid .passages therein and adapted to be traced with a liquid coolant, a plurality of titanium sublimators mounted in the housing on the outside of the shroud and adapted to direct its output toward the outer surface Iof the shroud.

S. A vacuum chamber as described in claim 7 including ion pump units `comprising cathode-anode assemblies and magnet assemblies mounted inside the housing and generally about the periphery thereof.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner. 

1. A VACUUM CHAMBER COMPRISING A GENERALLY CYLINDRICAL HOUSING HAVING AN ANNULAR ENLARGEMENT ABOUT A PORTION THEREOF, AN ION PUMP SUPPORT RING BEING SECURED TO THE INSIDE OF THE HOUSING AT SAID PORTION AND ABOUT THE PERIPHERY THEREOF, A PLURALITY OF ION PUMP ANODE-CATHODE ASSEMBLIES AND MAGNET MEANS, SAID ASSEMBLIES AND MAGNET MEANS BEING MOUNTED IN ALTERNATE FASHION ON AT LEAST ONE SIDE OF THE RING AND SPACED FROM THE WALL OF THE 